An “electronic nose” may one day be used to diagnose asthma, say researchers who presented a preliminary study of the device at the American Thoracic Society 2007 International Conference.

The device contains chemical vapor sensors that react to the presence of volatile organic compounds, or VOCs, in a person’s exhaled breath. “A person’s breath contains a mixture of thousands of VOCs that may be used as markers of lung disease,” says researcher Silvano Dragonieri, M.D., of Leiden University Medical Center in the Netherlands.

The electronic nose is a newer version of a sensor that has been used in the food, wine and perfume industries. It is also being used as an aid against terrorism, to sniff out explosives or toxic chemicals in the air.

An electronic nose responds to a given odor by generating a pattern, or “smell print,” which is analyzed and compared with stored patterns. An electronic nose has been developed that can diagnose respiratory infections such as pneumonia by comparing smell prints from the breath of a sick patient with those of patients with standardized readings. It is also being studied as a diagnostic tool for lung cancer.

In the new study, the researchers compared the “smell prints” of 20 people with diagnosed asthma (half with severe asthma and half with mild disease) and 20 people without asthma to see if the electronic nose could classify them as asthmatic or non-asthmatic. The subjects breathed into a face mask attached to a bag connected to the electronic nose.

The nose was able to detect which smell prints came from people with asthma, but was less accurate in classifying how severe a person’s asthma was. “The asthmatic patients in this study already had been diagnosed with asthma,” Dr. Dragonieri says. “The next step is to see whether the nose can diagnose new patients with asthma. It’s still a futuristic device – one day different electronic noses may be built to detect specific diseases.”